Brake mechanism



Nov. 20, 1951 T. R. MCGOWAN BRAKE MECHANISM 9 Sheets-Sheet 1 Filed March27, 1948 INVEN TOR. rlljfiowan Wm M MW am 3 mm W m flww w \m. 2% N .N L\MQQN x III] I J 2. l x l l l t-\ N l lllllll'll I 5 H dsw ww Q mm A mT- J mm k HIS ATTORNEY T. R. M GOWAN BRAKE MECHANISM Nov. 20, 195] 9Sheets-Sheet 2 Filed March 27, 1948 INI/"EN TOR. Thoma owan BY H15ATTORNEY NOV. 20, 1951 T. McGOwAN BRAKE MECHANISM 9 Sheets-Sheet 3 FiledMarch 27, 1948 HIS AT TOHNEY NOV. 20, 1951 T, MOGOWAN BRAKE MECHANISM 9Sheets-Sheet 4 Filed March 27, 1948 INVENTOR. Thom 12. M Goa/an HISATTORNEY T. R. M GOWAN BRAKE MECHANISM Nov. 20, 1951 9 shee i's-sheet 5Filed March 27, 1948 Fig. 7.

, JNVENTOR. T110122 R.MG0wazz 111s ATTORNEY NovwZO, 1951 T. R. M GQwA'N,5

- BRAKE MECHANISM Filed March 27, 1948 Fig: 4a.

INVENTOR.

Thom s lllflfiowan BY HIS AT TORNEY Nov. 20, 1951 T. R. MCGOWAN BRAKEMECHANISM Filed March 27, 1948 9 Sheets-sheaf 7' INVENTOR.

1 1 122. ff oz'van BY HIS ATTORNEY Nov. 20, 1951 T. R. M GDWAN 2,575,825

BRAKE MECHANISM Filed March 27, l948 9 Sheets-sheaf; 8

Fig 5a.

IN VEN TOR.

IILS' ATTORNEY T. R. M GOWAN Nov. 20, 1951 BRAKE MECHANISM 9Sheets-Sheet 9 Filed March 27, 1948 JNVENTOR. Tho/m6 1?. P1660100:

HIS ATTORNEY Patented Nov. 20, 1951 BRAKE MECHANISM Thomas R. McGowan,Pittsburgh, Pa., assignor to The American Brake Company, Swissvale, Pa.,a corporation of Missouri Application March 27, 1948, Serial No. 17,421

1 Claim. 1

My invention relates to brake mechanism for railway rolling stock, andparticularly to brake mechanism for use on a truck having at least threewheels on each side.

My invention is shown and described herein as applied to a six-wheelmotor truck for a diesel electric locomotive. While certain features ofmy invention are of particular utility in connection with such a truck,other features are of general utility.

In a motor truck of the type described, most of the space between thewheels is largely taken up by the driving motors and their associatedstructures. It is therefore necessary to mount most of the brake riggingoutside of the wheels. In order to provide adequate clearance betweenthe brake mechanism and roadside structures, the brake mechanism must bemade as small and compact as possible. Since the largest unit in thebrake mechanism is the brake operating cylinder, it is desirable to useas few cylinders as possible. If one cylinder is used to operate brakeshoes on several wheels, it must be connected to the brake shoes whichare located remote from it by a rather long and complex linkage,requiring a somewhat elaborate guiding and supporting structure. Suchguides and supports introduce friction which resists movement of thevarious parts of the linkage.

Friction in a brake rigging of the type in question presents nosubstantial problem during application of the brakes, because the poweravailable to apply the brakes is more than ample to overcome anyfriction which may be encountered. However, friction in the linkage mustbe taken into account in considering the releasing movement of thebrakes. Railway vehicle brakes are commonly arranged so that gravitytends to move them to their released positions. It is also common toprovide a spring acting on the piston of the brake operating cylinder ina releasing direction.

In a long and complex linkage such as that described above, gravity andthe release spring in the brake cylinder do not always insure equalreleasing travel of all the brake shoes. Wherever an equalizer lever isused in the linkage and the friction forces are different between theequalizer and the several shoes, then it is possible for one shoe to beretarded in its releasing travel more than another. The releasing forcesdue to gravity and the releasing spring in the operating cylinder maythen be expended in causing an overtravel of the shoe which is lessretarded by friction, while the shoe which is retarded travels less thanits designed releasing distance. The frictionally retarded shoe mayunder such 2 conditions be left in a position wherein it may engage thewheel, resulting in undesirable wear of both shoe and wheel.

It is therefore an object of my invention to provide a brake rigging ofthe type described including improved guiding and supporting structures.

Another object is to provide an improved brake releasing springarrangement.

A further object is to provide such a brake releasing spring arrangementfor use in connection with a brake rigging wherein a single cylinderoperates a plurality of brake shoes.

A further object is to provide an improved brake mechanism of the typeshown and claimed in Letters Patent of the United States No. 2,427,956,granted to William A. Gantner on Sep tember 23, 1947, for Brake Rigging.

According to my invention, I provide each wheel with a single brakeshoe, and I employ a brake cylinder for actuating the shoes associatedwith three wheels on one side of the truck. The piston rod of each brakecylinder is pivotally connected to the upper end of a brake cylinderlever which is secured at its lower end to a crank pivotally mounted onthe truck frame. Each crank is connected through a push connector with afirst horizontal equalizer lever at a point intermediate its ends. Thisequalizer lever is operatively connected at its inner end with a brakeshoe for the rear wheel of the truck. The outer end of this equalizerlever is operatively connected by means of a pull rod to :a slidablyguided pull link which extends longitudinally of the truck between thefirst and second wheels. A second equalizer lever has its outer endpivotally connected to'the pull link and its inner end operativelyconnected to a brake shoe associated with the front wheel of the truck.A second push connector connects an intermediate point on the secondequalizer lever with an in termediate point on a third lever whose outerend is pivotally attached to the truck frame and whose inner end isoperatively connected to the brake shoe on the center wheel of thetruck.

In one modification of my invention, I provide an improved guide andsupport bracketfor the first equalizer lever. This bracket cooperateswith an extension at one end of the push connector. The end opposite thebracket is supported by the crank so that the connector is supported atits opposite ends. I also provide improved guide and support means forthe pull link, by which that link is guided and supported at two spacedpoints. An improved brake releasingstructure is also provided,including, in addition to the releasing spring inthe brake cyl inder, anadditional spring having, in effect, a resilient lost motion connectionwith the first push connector and a slip friction connection with thefirst equalizer lever. This additional releasing spring insures that theequalizer lever returns to a definite angular position with respect tothe push connector'when the brakes are released. Since the releasingspring of the brake cylinder insures that the intermediate pointofi theequalizer lever returns to the same position;

each time, it may be seen that the two releasing springs togethercooperate to return all partsofi the brake rigging to their preselectedreleased.- positions. The slip-friction connection compensates for wearof the brake-shoes andwheels and insures that all the shoes are operatedthrough the same distances when the brakesare released. Y r

y Inanotlier modification of my invention,l use. a singlesupportingbracket for supporting both. the first push connector andthe' pull'rod.Also,v useasingle supporting bracket for one point on the pulllinkandthe outer end of the third lever: Also; in. this-modification, I-connect the additional brake releasing spring between the. pull link andtheframe; providing a yieldable lost motion connection between thespring and Figs. 2a and-2b together forma top plan view of the bra-kerigging of Figs; 1a and-1b,- showing that portionwhich-isattached'tooneside of the-truck. it being understood that the rigging onthe othersi'deof the-truck is-thecounterpart'of that shown. Fig'. 3- is a crosssectional viewtaken on the line arrows, with certainparts omitted forthe sake of, clarity: Figs: errand-4U together form a side elevational'"view' of a diesel electric locomotive truckiprovided with another-'-form of brakeriggi'ngfembodyingmyinvention.- 'Figs. 5a and 5btogether-form a top plan-view of the-brake mechanism in- Figs. 4a" and41), showing the brake mechanism for oneside of the truck only. Figs.6and 7 are cross sectional views taken on the line- V'I'VI and VI'I'VII,respectively. of' Fig. 4b,;looking'in the direction of'the'ar'rows,showin'gdetails'of the guiding and supporting mech-' anism:

Figs. 1 to. 3.

Referring; to thedrawings' the. reference characters I, 2', and 3designate respectively the front, middle, and rear wheels at the.right-hand side of a six-wheel motor truck for a diesel electriclocomotive. The left side of the truck is not shown, since it isprovided with brake rigging which is acounterpar't of that'described;

The brake rigging oomprises'a hanger lever 4 disposed at the rear sideof the front wheel I; a hanger lever 5 disposed at. the forward side ofthe middle wheel 2, and. a hanger lever B disposed at the forward sideof the rear wheel 3. The hanger levers are pivotally attached at theirupper" ends to the truck frame by means of pivot TII II-I of Fig. 2a;looking in thedirection of the 4 pins 7, and each hanger lever isprovided at its lower end with spaced jaws 8 which form a recess B. Abrakehead ii! is pivotally attached to each hanger lever intermediateits ends, and each brakehead carries a brake shoe ii for engagement withthe tread of the associated wheel. Thebraxkeheads ill for wheels 5 and3* are provided with stationary brakehead guides Gila (see Figs. 1 and3) having Wear plates iiib which engage thev brakehead pins I00 andthereby limit the lateral movements of the brakeheadsQ The; severalbrake: shoes are operated into and out of engagementwith theirassociated wheels by meansof-"a. fi'uid pressure motor including acylinder; l2. having a piston I3 movable therein. A spring is biases thepiston it in a brake releasing direction. The piston i3 operates apiston rod it, which is' operatively connected to the upper; end" of; a.brake cylinder; lever l he bralsea cylinder. lever i6 is pivotallysupported. on a. crankshaft. ii which extends through a hearing l8 inthe truck frame. bearing i8,the: crankshaft irlca-rries acrank arm i9:Which is pivotally. connected cto one cnd'of push connector; 26:. Nearits other. end thepush connector Zflgis. pivotally: connected to an.inter-- mediate point: on an; equalizer lever 29 mounted.

horizontally and extending transversely of the truck. The push connector20 is provided with an extensionfifia which extends heyondtheilever- 2tand is slid'ably. supportedby'a bracket 22 attached to the truckiramehThe. push connector 20- is: therefore supportedand guided against lat--eral' movement ation'e endby the bracket; 22- and: at its opposite endby the crankarm. 1.9., These widely" spaced supports provideamechanical. ad.- vantage for the reactive guiding. forces at thosepoints over laterally displacingv force. act-- ing on the push"connector2lli through thezequali zerlever 2 i The'inner endof equalizer lever 2iissecured within therecess in the hanger lever 6 by means of a pivot'pin 23 which-extends through registered openings formed in the'equalizerlever and in the jaws 8 of the-hanger.

The push connector rt" is provided with a laterally extending lug 2%which is apertured to loosely-receivea spring-rod 2s; The left end ofspring rod 24-, as it appears in the drawings, is flattened, as at-24 a,and is'provided with a slot 247). A collar'bolt Z5" is' fastened in asuitable aperture in lever Z I by'm'e'ans of a castellatedj lock nut 25;so thattheflangej or'colla'r 25a of the' c'ol lar bolt ishelcf againstthe upper surface of the j lever: The: upper end, of the collar: bolt 25ex'-' tends. through. the slot? 241). in springirod 2 1, and carriesacoiL spring?! which is heldjin compression hetweena Washer. 28"andal'ock nut 29'. The spring 21 holds the flattened portion 24aoispring. rod 24 frictionally-betweenwasher: 2c and collar 25a;thereby;- providing' a. slip-friction connection between spring rod:Z-andequalizer lever 21L A: coilspring: 30;. hereinafier referred; to asan auxili'aryrbrakezreleasihgspring,.surroundsithe'spring rodMonths-opposite side of lug 2th from the equalizer lever 24'. The spring35 is retained between washers S-I One washer 3| rests against the lugZeb. The otherwasher 3! is held on the rodZQ-by'means of'lock nuts32;

The: outeriend of equalizer lever 2i is pivotally connected to one. endor a pull rod 33,;whichextends; forwardly of the truck and is pivoted atits opposite end" to the rightend'of an intermediate beam 3 3; whichextends transversely of the truck;

On the inside of the Near its center, the pull rod. 33 is slidablysupported and guided by means of a bracket 35.

The intermediate beam 34 is pivoted by means of a pin 36 to a pull link31. The pull link 31 comprises upper and lower straps 31a and 37?), heldtogether by means of pin 36 and a pin 38 which connects the pull link3'! to the outer end of an equalizer lever 39. The upper strap 31aextends only a short distance beyond the pins 36 and 38. The lower strap31b of the guide rod 3'| extends considerably beyond the ends of theupper strap 31a, and has its ends slidably supported by brackets 40andAI, which are attached to the truck frame. These widely spacedsupporting brackets for the pull link 3! provide a considerablemechanical advantage for the reactive guiding forces over anytransversely acting displacing forces which may act on the pull link.The lower strap 31b is shown in Fig. 2b as somewhat wider than strap 31ain order to make the drawing clearer. It should be understood that thestraps may both be the same width, or if desired, the upper strap may bewider than the lower. The inner end of equalizer lever 39 is connectedby means of a pin 23 to the lower end of brake hanger 4. A pushconnector 42 is pivotally connected to an intermediate point on theequalizer lever 39, and has its opposite end pivotally connected to anintermediate point on a lever 43.

The push connector 42 includes a. slack adjuster 44 of well-knownconstruction. The outer end of lever 43 is pivoted on a fixed support 45attached to the truck frame. The inner end of lever 43 is pivotallyconnected to the lower end of hanger 5 by means of a pivot pin 23. i I

Operation of Figs. 1 to 3 the outer end of the equalizer lever 2| isgreater than the friction load on the inner end, this motion of the pushconnector first rotates the equalizer lever about the outer end as afulcrum,

thereby moving the inner end until the brake shoe II engages wheel 3.Thereafter the equalizer lever pivots about its inner end, and the outerend moves rearwardly, carrying the pullrod 33, intermediate beam 34, andpull link 31, along with it. This causes equalizer lever 39 to pivotabout the push connector 42 until its inner end moves far enough tocause engagementof brake shoe I I with wheel I. Thereafter the equalizerlever 39 pivots about its inner end, carrying the push connector 42rearwardly and causing the lever 43 to pivot in a counterclockwisedirection (as viewed in Fig. 2b) and. to move the brake shoe II intoengagement wtih wheel 2. Although the brake shoe for wheel 3 may touchits associated wheel first, the brake shoe for wheel I second and thebrake shoe for wheel 2 last, it should be appreciated that nosubstantial braking forces are applied to any of the wheels until all ofthe brake shoes are in engagement with their respective wheels. The.braking force applied at either end of either equalizer lever can be nogreater than the reactive force on the opposite end. The reactive forcescannot reach any appreciable value until the brake shoes are allengaging their associated wheels.

l It should be noted that, although the initial movement of equalizerlever 2| is in a direction to relieve the compressive force on spring30, the final movement of the equalizer lever to braking positioncompresses spring 30.

.When it is desired to release the brakes, the pressure in cylinder I2is released. The spring M then moves piston I3 and its associated partsback to their released positions. The spring I4 therefore insures thatthe intermediate point on equalizer lever 2| is restored to its normalposition. If the additional brake releasing spring 3|] were notprovided, it might be possible for either or both of the brake shoesassociated with the front wheels I and 2 to stick in or near theirbraking positions because of frictional forces between the variouselements of the linkage and their respective guides. In case of such asticking, the main release spring I4 could still return the pushconnector 20 to its normal position. The inner end of equalizer lever 2|would then travel slightly beyond its normal position to compensate forthe sticking of pull rod 33. However, when the additional spring 30 isprovided, it insures that the equalizer lever 2| returns to its normalangular position with respect to push connector 20. Therefore, it may beseen that the main releasing spring I 4 and the additional spring 30cooperate to return all parts of the linkage to their brake releasingpositions when the pressure is removed from cylinder I2. I

The spring 30 is so constructed that its coils close solidly upon eachother as soon as the spring rod 24 has traveled a sufficient distance topermit application of the brake shoes II to the wheels I and 2. Afterthe wheels and brake shoes have become worn, the braking positionrequired of the equalizer lever 2| will be somewhat displaced from itsoriginal braking position. After the coils of spring 30 have engagedeach other, if the brake shoes have still not engaged their associatedwheels, the equalizer lever 2| will be rotated additionally in aclockwise direction by the push connector 20. At this time, the springrod 24 cannot move rearwardly with respect to push connector 20. Theslip-friction connection between rod 24 and equalizer lever 2| thenallows the rod to slip over the equalizer lever until the brakes areapplied. When the brakes are again released, the lever 2| travelsthrough the same distance as before due to the action of springs I4 and30, but its released position is different, because of the movement ofthe slip-friction connection.

The slip-friction connection thereby insures that the distance betweenthe braking positions of the brake shoes and their released positionsremains substantially constant, even though the braking positionsthemselves may vary because of wear at the shoes and wheels.

Figs. 4 to 7 The brake mechanism shown in these figures is generallysimilar to that shown in Figs. 1 to 3. Elements in these figures whichare the counterparts of elements in Figs. 1 to 3 have been given thesame reference characters. These figures differ from the rigging shownin Figs. 1 to '3 chiefly in the details of the driving linkage whichoperates the several brake hangers, the guiding and supportingarrangement for that linkage, and in the location of the auxiliary brakereleasing spring.

The push connector 46, which corresponds generally to the push connector20 of Fig. 1, differs from the push connector 2|] in that it is not proas e 'z videdi asupporting: extension such; as 21m; nor; with, a:laterally: extending. 111g: such: as 20b: Theiouter endofi equalizer:lever -21ii isvconnectedi to one end of a pullrod' 471whose-.oppostiteend; isapivotedbon: a pull :link 48. The push connector46 and' the pull .rod=-4 i are bothsupportedzon a single bracket 49carried by a: strap Biicwhiclnis bif urcated' end of lever i3 isprovided with aper:-.

tures-whichreceive the pin5 l1, sothat thepin'fit forms a pivot: forlever: 4.3;

The pull link-48: also is supported andPguidedsby a bracket 531attach-edv to the frame of: the truck; upstanding. lug 5.4 isattachedvtothe upper surfaceiofthelpull link 18. Thelugleflris?apertturedxto. loosely receive aspringrod; 55:. The right" end. ofspring'rod 55.: iszfi'attened; .as at, 55a; and slotted as-at 55b, toreceive. apiniie'. The pin56: carries a: spring fi'iwhich'hol'ds; thespring rod 55. in frictional; engagement. with a lug. 53a formedz'onthebracket 53. The construction of pin 56and its associatedpartsisgeneraliy similar to theiconstruction" of. pin 25 and its. associatedparts. in Figs; 4. and 5 A release spring. 58-; is

coiled around the spring;v rod155 on thesideopfr positeithe bracket 53;.Theends of spring Ware retained by washers 59; one: adjacentthexlug 54andthe'. other held. 0111 the spring: hfiibymeans: of loclcnuts. 60:.

I Operation of Figs; 4-10? The operation oi pthe' rigging, shown in.Ei'gs. if to Tie generally similar to that. of the rigging, shown in,Figs. 1 to 3, and" it isbelievedthat, a ditional detailed explanation,is, unnecessary,

However, it shouldbe pointedout, that. the re:-

lease springufie insures a definite releasing travel of. the pullj link38' with respect to the'bracket .53., and hence with respect to. thetruckframe,

It thereby insures a definite, releasing, position of the outer endfoiequalizer lever 2!. As in the case of Figs. 1 to. 3, the. main releasingspring 1.14" associated with the brake. cylinder insures 7 that an.intermediate point of equalizer lever 2' li is'restored to adefinite;releaslnglposition. Since the releasing positions, of two points 'ontheequalizer lever 2i are; thus, determined, itj'ii's evident that itsreleasing position is definitely establishedand that the releasing.positions; of all'ithe. parts of the linkage. are. likewise. establi'shed.

The operation of the, release. spring 58 and of the slip,,-friction.connection. associated withpin 56'is substantially thesameasthe.operation of release spring 38 and the slip-friction con- 7 nectionassociated with: pin 25 in Figs. 1 to 3.

In this modification of my invention, the releasing spring 58; isintimately associated with the. particular part. of the; linkage most.likely to'become struck. That is, the pull link 48;,- .sinc e me from;the spirit .1 and SCDIQCZ-O fi my invention; Having: thus described: myinvention, what I claimaisz; V

. .In-a brakes mechanism} for; one. side of, aasix wheelrtruckcomprising" 9;; brake cylinder secured to the truckfimme; a. brakecylinder; lever securedss. at: its: lower end.v to. a crank pivotally;at,- tached to: the? truck: frame. and peratively, con.- nectedatits.tupperrendtwith saidybrakea cylinder; amushi connector; connected; at.oneend to; said crankaand .slidablyr supported at:.- the other. end, a.first: transversely extending. equalizer lever. pivotally connected;intermediate its: ends. with SQidYDHShL. connector intermediate itsends; and operativelyi connected at. its. inner end with, abrakeshoeaforcapplyingsa.brake to the rear one of:1the:trucl;wheels; a.pull rod; connected-to, the outer end oiisaidfequalizer lever andextending along the truck toward; the: front oi; the; truck, anintermediate beam, extending transversely of; the truck between thefront and middle wheel of theztruckand connected at one endto the otherend of: said, pull: rod, a, pull link; slidably supported forlongitudinal: movement with, respect: to the truck: and.operativelyconnected with said'rintermediate, beam in supportingrelationthereto; a. second transversely: extending equalizerleveroperatively connectecliat its outer end with. said pull link. and.operativelwcon: nested at. its. inner: end. with abmiieshoe forapplyingca; brake to. the; frontwheel; oi the truck; a. third;transversely;- extendings lever. pivotally attached: at; its outer: end?to; the. truck; frame and operatively. connected at its. inner: end;with a brake shoe for applying abraketothemiddlc wheel of the truck, anda second push connector connected at its ends with said second andthird. levers intermediate, their ends, the combination with theaforementio'ned instrumentalities ofmeans for insuring the release ofthebrakes. for the, first and. second wheels, irrespective offriction-in the linkage comprising a. lug projecting laterally from.said first push connector and having a hole therein, aspring.rodextendingwith. clearance, through said hole and Drovidedat one end;with av flattened portion having alongitudinal slot therein, a boltextendingthrough. said first equalizer. lever and through said; slot,spring means on said bolt for causing. frictional engagement between thespring rodtandnthe. lever, a spring retaineri'ixed on thespring, rod onthe side of the lug opposite the. equalizer lever and areleasing springon therocl between the lug and said retainer so arranged that .itscoilssolidly engageeach other after a predetermined deflection thereof.so that further movement. of the push connector after thespringcoilsengage each other cause slippage of the, spring rodirelative, tothe. lever to, coin.- pensat'e. for wear of. the brake, shoes and.wheels andmaintain the. same releasing travel of the brake shoes,

THOMAS..R.MCGOWANL REFERENCES; crime, The following references are ofrecord in the file ofthis patent-r I V UNITED STATES, PATENTS Number,-Name Date I 1,221,955. Sauvage; May 29, 1917 1,336,245 HedgcQCkl; -M.Dec. 15, 1931 2,210,038; Mueller. Aug. 6, 1940 2,402,389 Gantner June18,1946 1.423.956, Gantner; .Sept;.23; 1947

